The temporomandibular joint consists of the glenoid fossa, the condyle of the mandible, the disc between the fossa and condyle, and the musculoskeletal attachments of these structures. The mandibular fossa does not normally act as a part of a functional joint, but acts as a seat in which the condyle head moves or rests when the mouth is opened and shut. Injury or disease may affect the joint resulting in disfunction and severe pain. While many patients can be treated by nonsurgical methods, individuals who do not respond to such methods must be treated by surgical means. Surgical treatment using various implants has been the preferred method of treatment for those who do not respond favorably to more conservative treatment. Several of these implants have been described in the patent literature.
U.S. Pat. No. 3,178,728 to Christensen describes an implant of a metal fossa that was commonly used for treatment of ankylosis. The prosthesis was contoured to fit within the glenoid fossa and was shaped to overlay the articular eminence. The prosthesis was used extensively for treating cases of joint arthrosis or fibrous ankylosis.
U.S. Pat. No. 3,579,643 to Morgan discloses a device in the form of a sheet-like element contoured to overlay the articular eminence of the glenoid fossa.
U.S. Pat. Nos. 4,502,161 and 4,693,722 to Wall describe a prosthetic substitute for the condyle of the mandible which is used in conjunction with a prosthetic meniscus. The condyle is first removed surgically. The prosthetic condyle component comprises two plates between which is sandwiched the ramus of the mandible below the condylectomy site. One of the plates extends upward to form the prosthetic condyle having a convex surface. The method of surgical treatment taught therein requires extensive surgical intervention in an area containing the internal maxillary and masseteric arteries, the mandibular nerve and the branches of the facial nerve. The prosthetic meniscus used with the prosthetic condyle comprises a resilient insert shaped to be received in the glenoid fossa.
U.S. Pat. No. 4,917,701 to Morgan describes and claims a temporal implant component which is a thin, rigid plate contoured to generally conform to and overlay at least part of the articular eminence and mandibular fossa of the glenoid fossa. The component does not overlay the petro-tympanic fissure. A resilient, biologically inert material is securely attached to the superior surface of the rigid plate so that the resilient material is disposed to reside between the rigid plate and the floor of the mandibular fossa. The condyle prosthetic component disclosed therein comprises a thin, generally upright channel having a condyle molded of plastic material attached to the channel. The channel is shaped to slip over and wrap around the posterior border of the ramus from which the natural condyle has been removed. The area subjected to manipulation during the surgical procedure is the same as that of U.S. Pat. No. 4,693,722 of Wall. Hence, the problems related to site of surgical intervention discussed above are not avoided by the methods of Morgan.
U.S. Pat. No. 4,778,472 to Homsy, et al. describes and claims a temporomandibular prosthesis wherein the prosthetic condyle articular face with a heel extending backwardly from the face and a toe extending forwardly from the face. The condyle is shown as a part of a component having a plate which is attached in the region of the ramus. There is no disclosure of how the plate is to be attached to the mandible. In fact, there is no disclosure of the surgical procedure required to implant the device. Moreover, several complications have arisen as a result of using the device of Holmsy, et al., including, but not limited to, the disintegration of the PROPLAST with resulting injurious tissue response.
U.S. Pat. No. 4,936,852 to Kent, et al. discloses a minicondyle that covers a natural condyle wherein the diseased portion has been excised. It is asserted in that disclosure that the use of the mini prosthesis of the invention optimized the TMJ function through improved adaptability during surgery. However, the area in which the surgical activity is performed is in the region of the internal maxillary artery and a branch of the facial nerve.
European patent publication 290-138-A of Pollock describes a set of fasteners for holding bone together. There is no teaching therein that the fasteners decribed therein would be appropriate for use to support an artificial condyle or any other prosthetic device.